The present invention relates primarily to pressure testing the coolant systems of the internal combustion engine, and more particularly to a compressed air operated pressure tester for performing diagnostic services on water cooled engines and their related components. Although the invention will be described in that environment, it will become perceptible to those proficient in the trade, that the pressure tester divulged herein may find appropriate uses in other circumstances where it is desired to inspect the pressure integrity of closed systems.
Most internal combustion engines employ a liquid cooling system to maintain the engine within an ideal range for operating efficiency. The fluid typically being water with particular additives. The cooling system of such internal combustion engines generally utilize liquid flow paths that extend within the engine block where heat is transferred from the operating engine to the liquid, through a water pump which circulates the liquid, and then through a radiator where heat transfer occurs between the liquid and the air. With the arrival of higher performance engines, the use of smaller radiators due to costs, design restrictions, and higher operating temperatures for the engines, a substantial amount of heat is generated which has to be dispelled through a comparably small area consisting of the radiator surface. As a result, the majority of these cooling systems operate under pressure. By pressurizing the system, the boiling point of the coolant is raised, resulting in less loss of coolant by evaporation with a relative boost in cooling efficiency.
The amount of pressure formed in these cooling systems depends largely on the temperature of the coolant and the velocity at which the engine is operated. Since the cooling system is designed to be a closed system, any slight leaks existing anywhere in the flow passages will diminish the efficiency of the system and excessive loss of coolant can occur.
As the coolant is lost through such leaks, the efficacy of the system to keep the engine temperature from rising above the ideal operating degree, is consequently decreased. If enough of the coolant is lost, overheating transpires which will more than likely damage the engine.
Therefore, it is recognized that cooling systems of internal combustion engines should be pressure tested periodically to ascertain the presence of leaks by measuring the integrity of the cooling system.
A heater is also incorporated in the cooling system of most vehicles. It is usually located near to or inside of the vehicle. The heater is normally connected to the other parts of the cooling system by a heater supply conduit.
If a leak is shown when using the most commonly used tool, a hand operated air pump and gauge unit, it is not always easy to determine where the leak is located. The typical engine cooling system is liuqid filled except for a small volume of air located at the top of the radiator, the highest point in the cooling system. The air pressure in that segment of the radiator is increased by the hand pump which is connected to the radiator filler neck at the top of the radiator. Consequently, any leak that might be in the air-filled section of the radiator can only be discovered by the presence of escaping air which cannot be seen by visual observation.
It is further hoped that the invention's ease of use will be obvious as compared to the current standard of the industry being a hand pumped unit with limited safety valving. Rather than having the operator manually pump air into the system while having removed himself from any test procedure as he supplies the air for the test.
The invention uses this compressed air supply to make test procedures easy to accomplish, and expand the technician's ability to diagnose the condition of the components of the cooling system. Most vehicle repair shops supply compressed air.